Hands On With A Batteryless E-Paper Display

June 17, 2020 by Donald Papp 64 Comments

E-paper displays are unusual in that power is only needed during a screen update. Once the display’s contents have been set, no power whatsoever is required to maintain the image. That’s pretty nifty. By making the display driver board communicate wirelessly over near-field communication (NFC) — which also provides a small amount of power — it is possible for this device to be both wireless and without any power source of its own. In a way, the technology required to do this has existed for some time, but the company Waveshare Electronics has recently made easy to use options available for sale. I ordered one of their 2.9 inch battery-less NFC displays to see how it acts.

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New Part Day: Battery-Less NFC E-Paper Display

March 22, 2020 by Erin Pinheiro 30 Comments

Waveshare, known for e-ink components aimed at hobbyists among other cool parts, has recently released a very interesting addition to their product line. This is an enclosed e-ink display which gets updated over a wireless NFC connection. By that description, nothing head-turning, but the kicker is that there is no battery inside the device at all, as it harvests the energy needed from the wireless communication itself.

Just like wireless induction charging in certain smartphones, the communication waves involved in NFC can generate a small current when passing through a coil, located on this device’s PCB. Since microcontrollers and e-ink displays consume a very small amount of current compared to other components such as a backlit LCD or OLED display, this harvested passive energy is enough to allow the display to update. And because e-paper requires no power at all to retain its image, once the connection is ended, no further battery backup is needed.

The innovation here doesn’t come from Waveshare however, as in 2013 Intel had already demoed a very similar device to promising results. There’s some more details about the project, but it never left the proof of concept stage despite being awarded two best paper awards. We wonder why it hadn’t been made into a commercial product for 5 years, but we’re glad it’s finally here for us to tinker with it.

E-paper is notorious for having very low refresh rates when compared to more conventional screens, much more so when driven in this method, but there are ways to speed them up a bit. Nevertheless, even when used as designed, they’re perfectly suited for being used in clocks which are easy on the eyes without a glaring backlight.

[Thanks Steveww for the tip!]

Get Organized With This Raspberry Pi E-Ink Calendar

February 11, 2019 by Tom Nardi 15 Comments

Like many hackers, we love e-ink. There’s something mesmerizing and decidedly futuristic about the way the images shift around and reconstitute themselves. Like something from Harry Potter, but that you can buy on Alibaba instead of from a shop in Diagon Alley. But as anyone who’s used the technology can tell you, the low refresh rate of an e-ink screen limits its potential applications. It works great for reading books, but beyond that its struggled to find its niche in a world of cheap LCDs.

But [Zonglin Li] has recently wrapped up a project which shows that e-ink has at least one more use case: personal calendars. You can get way with only updating the screen once a day so the refresh rate won’t matter, and the rest of the time it’s going to be static anyway so you might as well enjoy the energy savings of leaving the screen off. With a Raspberry Pi behind the scenes pulling data from the Internet, it can populate the calendar with everything from your personal schedule to when your favorite podcast drops.

In practice, [Zonglin] is actually updating the display every hour as he’s included the current weather conditions on the top left of the screen, but even still, this is a perfect application for the very unique properties of e-ink displays. The display is a 7.5 inch 640×384 model from Waveshare that retails for about $50 USD, so between the display, the Raspberry Pi, and something to put it all in (here, a picture frame) this is a pretty cheap build compared to some of the large format e-ink displays out there.

The software side is written in Python 3, and [Zonglin] has documented how others can easily plug in their own information so it can pull schedule data from Google Calendar and local conditions from Open Weather Map. The MIT licensed source code is also very well organized and commented, so this could serve as an excellent base if you’re looking to create a more comprehensive e-ink home information display.

If this seems a little too pedestrian for your tastes, you could always put together an e-ink movie player, a surprisingly functional Linux terminal, or a very slick ESP8266-based name tag. If you’ve got the better part of $1K USD and don’t know what to do with it, you could even get an e-ink license plate.

Raspberry Pi Jukebox Hits All The Right Notes

January 22, 2019 by Tom Nardi 2 Comments

We (and by extension, you) have seen the Raspberry Pi crammed into nearly every piece of gear imaginable. Putting one inside a game console is so popular it’s bordering on a meme, and putting them into old stereos and other pieces of consumer electronics isn’t far behind. It’s always interesting to see how hackers graft the modern Raspberry Pi into the original hardware, but we’ll admit it can get a bit repetitive. So how about somebody scratch building an enclosure for their jukebox project?

[ComfortablyNumb] took the road less traveled when he created this very nice wooden Raspberry Pi enclosure in the shape of an eighth note. Stained and varnished and with a nice big touch screen in the middle to handle the controls, it’s an attractive and functional piece of home audio gear that we imagine most people would be happy to hang on their wall.

The process starts by printing out the desired shape on a piece of paper to use as guide, and then gluing together strips of wood to create the rough outline. Then the surface was thoroughly sanded to bring all of the strips of wood to the same level, and the final design was cut out. On the back of the note, [ComfortablyNumb] boxed out an area to hold the Waveshare seven-inch touch screen panel and the Raspberry Pi itself.

Having seen so many projects where the Pi is rather unceremoniously shoehorned into another device, it’s refreshing to see the results of a purpose-built enclosure. Since [ComfortablyNumb] was able to build the electronics compartment to his exact dimensions, the final result looks exceptionally clean and professional. Not a drop of hot glue to be seen. It also helps that this build only required the Pi and the display; as the device is meant to be plugged into an existing audio setup, there’s no onboard amplifier. The audiophiles out there might recoil in horror, but adding a dedicated digital to analog converter (DAC) would be easy enough to add if the stock audio on the Pi isn’t good enough for you.

The project is finished off with stain and several coats of varnish to get that deep and rich color. We don’t often find ourselves working with dead trees around these parts, but we’ve got to admit that the final product does look quite handsome. Certainly beats the LEGO cases many of our Pi projects live in.

If you’re looking for more wooden-encased Pi jukeboxes, you might enjoy this somewhat abstract magstripe-based take on the concept. Of course, we’ve also seen our fair share of actual jukeboxes receive a Raspberry infusion over the years.

[via /r/raspberry_pi]

E-ink Typewriter Is Refreshingly Slow

October 20, 2018 by Ben James 31 Comments

It’s pretty hard to use the internet to complete a task without being frequently distracted. For better or worse, there are rabbit holes at every turn and whilst exploring them can be a delight, sometimes you just need to focus on a task at hand. The solution could be in the form of distraction-blocking software, razor-sharp willpower, or a beautifully crafted modern “typewriter”. The constraint and restriction of a traditional typewriter appealed to [NinjaTrappeur], but the inability to correct typos and share content online was a dealbreaker. A hybrid was the answer, with a mechanical keyboard commanding an E-ink display driven by a Raspberry Pi.

The main point of interest in this build is the E-ink screen. Though it’s easy to acquire theses displays in small sizes, obtaining a screen greater than four inches proved to be a challenge. Once acquired, driving the screen over SPI was easy, but the refresh rate was horrific. The display takes three seconds to redraw, and whilst [NinjaTrappeur] was hoping to implement a faster “partial refresh”, he was unable to read the appropriate values from the onboard flash to enable manual control of the drawing stages. Needless to say, [NinjaTrappeur] asks if people have had success driving these displays at a more usable rate, and would love to hear from you if so.

Some auxiliary hacks come in the form of terminal emulator adaptation, porting the E-ink screen library from C++ to C, and capturing the keyboard input. A handmade wooden case finishes it off.

If it’s old-school typewriters that float your boat, we’ve got you covered: this solenoid-actuated typewriter printer eventually became a musical instrument, and this daisy wheel machine produces ASCII art from a live camera.

[Via Boing Boing]

Run A Linux Terminal On Cheap E-Ink Displays

August 14, 2018 by Tom Nardi 49 Comments

If you haven’t kept up with the world of e-ink displays, here’s some good news: they are pretty cheap now. For as little as $15 you can get a small e-ink display that has good enough performance and contrast to actually do something useful. There’s only one problem: figuring out how to drive them in your project.

Tired of seeing nothing but wiring diagrams and sample code when it came to actually putting these e-ink modules to use, [Jouko Strömmer] decided to try his hand at creating a turn-key application for these gorgeous little displays. The result is PaperTTY, a Python program that allows the user to open up a fully functional Linux virtual terminal on an e-ink display.

Of course, there are some caveats. For one, this all assumes you’re using a Waveshare display (specifically their 2.13 inch HAT) connected to a Raspberry Pi over SPI. Not to say that’s the only hardware combination that will work, but it’s the only one that [Jouko] has done any testing on at this point. If you want to try to shake things up in terms of hardware, you might need to get your hands dirty.

The advantage of being able to open a Linux VT on one of these e-ink displays is pretty simple: you can run basically any piece of software you want on it. Rather than having to come up with software that specifically features support for the display, you can just use (or write) standard Linux console programs. [Jouko] mentions a number of popular programs such as vim and irssi, but you could just as easily write a Bash script to dump whatever data you like to the screen.

In the video after the break [Jouko] shows PaperTTY in action for the doubters who think these sorts of displays are no good for interactive use. The display is very crisp and readable, with no signs of flickering. Overall he says the experience is not unlike using a slow SSH connection. It might not be how we’d like to use a computer full time, but we can definitely see the potential.

With the recent progress with Kindle hacking, it seems that interest in e-ink is as high as ever. Despite what the haters might claim, it’s a useful niche tech that still holds plenty of promise.

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Breadboarding With E-Paper

September 13, 2017 by Al Williams 25 Comments

[David Watts] picked up an inexpensive Waveshare e-Paper display. He made a video about using it with a breadboard, and you can see it below.

The E-Paper or E-Ink displays have several advantages. They are low power, they retain their display even without power, and they are very visible in direct light. The downside is they don’t update as fast as some other display technologies.

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